Iowa-Nebraska Equipment Dealers Association Inc. has acquired a 3.3-acre site in Johnston and plans to construct a 4,500-square-foot office building. Andrew Goodman, the trade association’s president, said construction is expected to begin on June 1 and take six months to complete. The organization plans to relocate to the proposed one-story owner-occupied building from a business condominium at 1311 50th St. in West Des Moines. That property will be listed for sale, Goodman said. The association, which acquired the vacant parcel at 5361 Stoney Creek Drive for $220,000, has selected Hansen Co. Inc. as the general contractor and SVPA Architects Inc. as the project architect. The land has an assessed value for tax purposes of $234,500. The sale closed on Feb. 24.